From 32572618cdcc36162b5769eb4c71964db9734061 Mon Sep 17 00:00:00 2001

From: fujiwarat <takao.fujiwara1@gmail.com>

Date: Tue, 6 Aug 2019 18:55:14 +0900

Subject: [PATCH] bus: Exit ibus-daemon with parent's death

ibus-daemon can be restarted unexpectedly during logging out the session

and double ibus-x11 prevent from enabling XIM in XGetSelectionOwner()

for the "ibus" atom.

ibus-daemon always will exit the process when the parent process dies

to avoid this problem.

---

 bus/main.c   | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++-

 configure.ac |  3 +++

 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/bus/main.c b/bus/main.c

index 3223d541..e11a5ebd 100644

--- a/bus/main.c

+++ b/bus/main.c

@@ -32,6 +32,10 @@

 #include <sys/stat.h>

 #include <unistd.h>

+#ifdef HAVE_SYS_PRCTL_H

+#include <sys/prctl.h>

+#endif

+

 #include "global.h"

 #include "ibusimpl.h"

 #include "server.h"

@@ -164,6 +168,15 @@ _sig_usr2_handler (int sig)

     g_mem_profile ();

 }

+#ifdef HAVE_SYS_PRCTL_H

+static void

+_sig_usr1_handler (int sig)

+{

+    g_warning ("The parent process died.");

+    bus_server_quit (FALSE);

+}

+#endif

+

 gint

 main (gint argc, gchar **argv)

 {

@@ -204,7 +217,7 @@ main (gint argc, gchar **argv)

     /* daemonize process */

     if (daemonize) {

         if (daemon (1, 0) != 0) {

-            g_printerr ("Can not daemonize ibus.\n");

+            g_printerr ("Cannot daemonize ibus.\n");

             exit (-1);

         }

     }

@@ -276,6 +289,47 @@ main (gint argc, gchar **argv)

             exit (-1);

     }

+    if (!daemonize) {

+        if (getppid () == 1) {

+            g_warning ("The parent process died.");

+            exit (0);

+        }

+#ifdef HAVE_SYS_PRCTL_H

+       /* Currently ibus-x11 detects XIOError and assume the error as the

+        * desktop session is closed and ibus-x11 calls Exit D-Bus method to

+        * exit ibus-daemon. But a few desktop sessions cause XError before

+        * XIOError and GTK does not allow to bind XError by applications and

+        * GTK calls gdk_x_error() with XError.

+        *

+        * E.g. GdkX11Screen calls XGetSelectionOwner() for "_XSETTINGS_S?"

+        * atoms during the logout but the selection owner already becomes

+        * NULL and the NULL window causes XError with

+        * gdk_x11_window_foreign_new_for_display().

+        *

+        * Since ibus-x11 exits with XError before XIOError, gnome-shell

+        * can detects the exit of ibus-daemon a little earlier and

+        * gnome-shell restarts ibus-daemon but gnome-shell dies soon.

+        * Then gnome-shell dies but ibus-daemon is alive, it's a problem.

+        * Because it causes double ibus-x11 of GDM and a login user

+        * and double XSetSelectionOwner() is not allowed for the unique

+        * "ibus" atom and the user cannot use XIM but not GtkIMModule.

+        *

+        * Probably we could fix the ibus process problem if we would fix

+        * XError about the X selection owner or stop to restart ibus-daemon

+        * in gonme-shell when the session is logging out.

+        * Maybe using SessionManager.LogoutRemote() or

+        * global.screen.get_display().get_xdisplay()

+        * But I assume thereare other scenarios to causes the problem.

+        *

+        * And I decided ibus-daemon always exits with the parent's death here

+        * to avoid unexpected ibus restarts during the logout.

+        */

+        if (prctl (PR_SET_PDEATHSIG, SIGUSR1))

+            g_printerr ("Cannot bind SIGUSR1 for parent death\n");

+        else

+            signal (SIGUSR1, _sig_usr1_handler);

+#endif

+    }

     bus_server_run ();

     return 0;

 }

diff --git a/configure.ac b/configure.ac

index f1df3ac1..fdd316a9 100644

--- a/configure.ac

+++ b/configure.ac

@@ -140,6 +140,9 @@ AC_HEADER_STDC

 LT_INIT

 IT_PROG_INTLTOOL([0.35.0])

+# Check header filess.

+AC_CHECK_HEADERS([sys/prctl.h])

+

 # Check functions.

 AC_CHECK_FUNCS(daemon)